1. Field
The described technology relates generally to a rechargeable battery and a battery module.
2. Description of the Related Art
A rechargeable battery differs from a primary battery in that it can be repeatedly charged and discharged, while the latter makes only the irreversible conversion of chemical to electrical energy. A low-capacity rechargeable battery is used as the power supply for small electronic devices, such as cellular phones, notebook computers and camcorders, while a high-capacity rechargeable battery is used as the power supply for driving motors in hybrid vehicles and the like.
A high-power rechargeable battery using a non-aqueous electrolyte with a high energy density has been recently developed. For example, the high-power rechargeable battery is constructed with a high-capacity rechargeable battery having a plurality of rechargeable cells coupled to each other in series such that it can be used as the power supply for driving motors in electric vehicles requiring high power.
Furthermore, one high-capacity rechargeable battery is commonly formed with a plurality of rechargeable cells coupled to each other in series. The rechargeable battery may have a cylindrical shape, a prismatic shape, etc.
Rechargeable batteries typically include an electrode assembly having a positive electrode, a negative electrode, and a separator therebetween, and an externally protruding terminal. A positive electrode current collector is made of aluminum and a negative electrode current collector is made of copper, and thus a positive electrode terminal electrically connected with the positive electrode is made of aluminum and a negative electrode terminal connected with the negative electrode is made of copper.
The positive electrode current collector and the positive electrode current collector are made from the same material and the negative electrode current collector and the negative electrode are the same material because often different materials cannot be easily bonded to each other by welding and a portion where the different materials are welded is relatively weak in strength.
Furthermore, when the positive electrode and the negative electrode are made of different materials, contact resistance between a connection member and the terminals is increased when the connection member is bonded to the terminals by welding, and the welding portion is weak to vibration due to low strength.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.